1. Field of the Invention
The present invention relates to a pipelayer.
2. Background Information
A pipelayer is a work vehicle used for installing pipes at petroleum and natural gas delivery pipeline construction sites and the like. For example, at a pipeline construction site, multiple pipelayers are lined up in a row and the pipelayers hoist a wire using a winch to lift up the pipes. The winch is connected to a hydraulic motor and rotated by hydraulic pressure.
Warming up is performed to raise the temperature of the hydraulic fluid in the pipelayer. For example, a pipelayer described in International Publication WO 2012-086695 has a pump hydraulic circuit connected to a hydraulic pump, a drive hydraulic circuit through which the hydraulic fluid for driving the hydraulic motor passes, and a warm-up hydraulic circuit through which the hydraulic fluid for warming up the hydraulic motor passes. A winch control valve is disposed between the pump hydraulic circuit and the drive hydraulic circuit. A warm-up control valve is disposed between the pump hydraulic circuit and the warm-up hydraulic circuit.